Buffing device for railway switches and the like



2, 1932. w, Q MCWHIRTER 1,869,605

BUFFING DEVICE FOR RAILWAY SWITCHES AND THE LIKE.

Original Filed sept. 11. 1929 2 Sheets-Sheet l l I I INVENTORIN WhlFtH 1932- w. c. MOWHIRTER 1,869,605

BUFFING DEVICE FOR RAILWAY SWITCHES AND THE LIKE Original Filed Sept. 11, 1929 2 Sheets-Sheet 2 P is INVENTOR: 14 .MaWh/rter,

BY V

A 4; ATTORNEY.

Patented Aug. 2, 1932 UNITED STATES PENNSYLVANIA.

PATENT OFFICE.

WILLIAM C. MCWHIRTER, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWI SSVALE, PENNSYLVANIA, A. CORPORATION OF BUFFING DEVICE FOR. RAILWAY SWITCHES AND THE LIKE Original application filed September 11,1929, Serial No. 391,801. Divided and this application filed December 8, 1930.

My invention relates to buifing devices for ment ofthe switch from one extreme position to the other by a switch operating device, and which will permit the switch points to be fully moved away from either extreme position by a trailing railway vehicle, but which will retard the return of the switch points to their initial positions after such vehicle has trailed through the switch.

The present application is a division of my copending application filed September 11, 1929, Serial No. 391,801, for buffing devices for railway switches and the like.

I will describe one form of buffing device embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a top pla'n'view, partly cross-sectioned, showing a spring switch provided with one form of buffing device embodying my invention. Fig. 2 is an enlarged right-hand end view of the buffing device shown in Fig. 1. Fig. 3 is an enlarged sectional view on the line HIIII of Fig. 1. Fig. 4 is a sectional view on the line IV-IV of Fig. 2, and Fig. 5 is a sectional view on the line V-V of Fig. 2. I 7

Similar reference characters refer to simi? lar parts in each of the several views.

Referring first to Fig. 1, the reference character A designates a railway switch, and the reference character B designates a device for operating it. The switch A comprises, as usual, two fixed rails 1 and 1 and two movable switch points 2 and 2 the switch points being connectedtogether near their tips by a front rod 3. I

The operating device B, as here .shown, comprises a switch stand'l having its base 4 spiked or otherwise secured to the ties adjacent the switch A. A gear shaft 6 is jour naled in the switch stand l and carries a crank 5, and a gear segment 7. The gear segment 7 meshes with a bevel pinion 8 keyed to a pinion shaft 9. The pinion shaft 9 ex tends through the side of the switch stand t and has attached to its outer end the usual weighted switch throwing; lever 10.

. end

Serial No. 500,776.

The crank 5' of the switch throwing device .B isconnected with the front rod 3 of switch Aby means of a link 11 and a spring connecting rod C. The spring connecting rod C may have. any suitable form, but in the well known form here, shown, this connecting rod comprises a cylindrical housing 14 hav inga lateral, extension l l fastened to the front rod 3. The right-hand end 14" of the housing 14 has a smaller diameter than the body of the housing, while the left hand is threaded to receive a cap 15 having an end '15 similar to. the end 14?. Slidably mountedvin. the opening in the end 14 is a sleeve 16 provided with an annular flange 16 located within the housing l gand similarly mounted in the opening in the end 15 is a sleeve 17 provided with an annular flange 17 located within the housing 14. A spring rod 12 extends through both sleeves 16 and 17 with suflicient cleanance to permit the rod to slide freely in the sleeves, and this rod carries acompression spring 78 which engages the sleeves at the annular flanges and urges the sleeves toward the positions in which the annular flange 16 of the sleeve 16 engages the shoulder formed on theinside of the housing 14 by the end 14*, and the annular flange 17 of the sleeve 17 engages the shoulder formed on the inside of the cap 15 by the end 15 The spring rod 12 is provided with an annular shoulder 13 for at times engaging the outer'end of the sleeve 16, and with a nut 18 for'at times engaging the outer end of the sleeve 17. The right-hand end of the spring rod 12 is pivotally attached to the link 11."

- The apparatus thus'far described is well known in the art and its operation will be readily understood from an inspection of the drawings.

The front rod 3 is also connected by means of an adjustable link 21 with the piston 'rod 31, of a buifing device D. The buffing device D in the form here shown comprises a casing 23 provided with two integral'trunnions 77 and 77 '(see Figs. 2 and 3) by means of which thebufling device may be pivotally supported in any suitable manner. As here shown, the buffing deviceis pivotally sup a cylinder head 26 bolted to the casing 23 by means of bolts 28, and at the other end by a cylinder head 27 bolted to the casing 23 by means of bolts 29. The piston rod 31 eX- tends into the cylinder 23 through a stulling box 30 and through a suitable opening 27 in the cylinder head 27, and is fastened to two spaced reciprocable pistons 24 and 25. he cylinder 23 is intended to be filled witha suitable fluid such as oil, and the stuffing box 30 forms a fluid-tight joint through which the piston rod may slide.

The cylinder wall is provided-at its lefthand end with a leak groove 23 and at its right-hand end with a similar leak groove 23. The function of the grooves 23 and 23 is to permit fluid to flow past the pistons under certain conditions as will be made clear hereinafter. v

The upper part of the casing 23 has formed therein a reservoir 23 (see Figs. 3, 4 and 5), which may also be filled with fluid. The cylinder 23 is constantly connected, near its center, with this reservoir by means of an opening 33 in the cylinder wall. .As shown in Fig. 4, the left-hand end of the cylinder 23 is connected with this reservoir through a port 68, a regulating valve 58, and two ports 69 and 70. The regulating valve 53 may have any suitable form, but in the form here shown, this valve comprises a cylindri cal valve member 58 fitting within a hole 61 in the cylinder head 26, and attached-to a valve stem 58 The valve member 58 is provided with a plurality of restricted orifices 58, one or more of which may be brought into registration with the port 69 by turning the valve member 58 To facilitate turning the valve member 58 the valve stem '58 is provided in its upper end with a saw kerf 58 adapted to receive the end of a screw driver. The valve 58 is held in place by a gland 59 which surrounds the valve stem 58*, and which is fastened to the cylinder head 26 by means of two stud bolts 62 which pass through suitable holes in the gland and which are screwed into threaded holes (not shown) in the cylinder head 26. Suitable packing 60 is inserted between the gland 59 and-the shoulder formed atthe top of the valve member 58 to prevent fluid from leaking past the valve.

The left-hand end of cylinder 23. isalso connected with the reservoir 23 through two coaxial ports 34 and 35, as best seen in Fig. 5. The flow offluid through these ports is controlled by a poppet valve F comprising a alve member 36, carried by a valve stem 37, and cooperating with a valve seat 34 formed in the end of the port 34. The right-hand end of the valve stem 37 is fluted and extends into the ports 34 and 35, while the left-hand end of the valve stem 3'? slides in a guide bearing 39 formed in a plug 40 screwed into a threaded opening in the cylinder head 25. A spring 38 having one end located in an annular recess 41 in the plug 40, to center the spring with respect to the valve stem 37, e the valve member 36 and constantly urges the valve member towards the valve seat 34.

The right-hand end of the cylinder 23 is connected with the reservoir 23 through a port 71, a regulating valve 63, and two ports 72 and 73 (see F ig. 4) The regulating valve 63 is similar to the regulating valve 58, and

'comprisesa cylindrical valve member 63 fitting in a hole 67 in the cylinder head 27 and attached to a valve stem 63. The valve member 63 is provided with a plurality of restricted orifices 63, one or more of which may be brought into registration with the port 72 by turning the valve member 63". The upper end of the valve stem 63 is provided with a saw herf 63. A gland 64 surrounds the valve stem 63 and is fastened to the cylinder head 27 by means of stud bolts 65, packing $5 being inserted between the gland and the shoulder formed at the upper part of the valve member 63 to prevent fluid from leaking past the valve.

The right-hand end of the cylinder 23" is also connected with the reservoir 23 through two coaXial ports 42 and 43. The flow of fluid through these ports is controlled by a poppet valve G similar to the poppet valve F described hereinbefore. As here shown. the poppet valve G comprises a valve member 44 carried by a valve stem 45 and cooperating with a valve seat 43 formed in the end of the port42. The left-hand end of the valve stem 45 is fluted and extends into the ports 42 and 43, while the right-hand end of the valve stem 45 is adapted to slide in a guide bearing 47 formed in a plug 48. The plug 48 also has formed therein an annualr recess 49 which receives one end of a coil spring 46. The other end of the coil spring 46 engages the valve member 44 and constantly urges the valve member 44 towards the valve seat 43 The valves F and G are operated by two tappets 53 and 54, respectively, which, in turn, are actuated by a cam 5O formed by cutting away a portion of a cam shaft 50, as best seen in Figs. 3 and 5. I The tappet 53 is slidably mounted in two lugs 55 projecting upwardly from the wall of the cylinder 23 into the reservoir 23, and the tappet 54 is similarly mounted in two similar lugs 53. The cam shaft 50 is journaled in two bearings 51 and 52 screwed into the upper part of the casing 23 as best seenin Fig. 3. The

outer ends of thecam shaft 50 are provided with threaded holes 50 and 50 into the most convenient one of which may be screwed a crank arm for operating the cam shaft. As here shown, a crank arm 57 is screwed into the hole 50 and the free end of this arm is pivotally connected with one end of an adjustable operating rod 20, the other end of which is connected with the spring rod 12 by meansof a screw jaw 19. The parts are so proportioned that when switch A occupies its normal position, in which position it is illustrated in the drawings, the cam 50 is rotated out of engagement with the tappet 53 and into engagement with the tappet 54 so that valve F is closed and valve G is open. hen switch A occupies its reverse position, however, the cam 50 is rotated out of engagement withthe tappet 54 and into engagement with the tappet 53 so that valve F is opened and valve G is closed.

To facilitate the insertlon of fluid into the cylinder 23? and the reservoir 23, a screw plug 7 6 is provided in the trunnion 77 as best seen in Fig. 3. I

The operation of the apparatus as a whole is as follows: When switch A occupies its normal position in which position it is illustrated in Fig. 1, the parts of bufiing device D are in the positions shown in Figs. 4 and 5; that is, valve F is closed, valve G is open, and pistons 24 and 25 occupy their extreme left-hand positions. If, now, switch A is moved from its normal to its reverse position by switch operating device B, pistons 24 and 25 of buffing device D are moved toward the right a corresponding amount, and cam 50" is rotated in a counterclockwisedirection. The construction of cam 5O is such'that during this movement of the switch, 'valve G of buffing device'D is held open until after piston 25 has moved past the left-hand end of leak groove 23 and valve F is opened as soon as piston 24 has reached the righthand end of leak groove 23. As a result, during this movementfluid flows from cylinder 23 on the right-hand side of piston 25 past valve G into reservoir 23", until piston 25 passes the left-hand end of leak groove 23 (see Fig. 5),whereupon, valve G closes, and fluid on the right-hand side of piston 25 thereafter flowsthrough leak groove, 23 into cylinder 23 between pistons 24 and 25. During this movement, fluid also; flows from cylinder 23 between pistons 24 and 25 through lea-k groove 23 lIllIOLCYllIlClBI 23 on the left-hand side of iston '24 until piston 24 passes the right-hand end of leak groove 23, whereupon, valve F opens and fluid then flows from reservoir 23 into cylinder 23 on the left-hand side of-piston' 24 through valve F. It will be apparent, therefore. that during the movement of the switch A from its normal to its reverse position by the switch operating device B, the'fluid in cylinder 23 If, when switch A occupies its'reverse posii tion, the switch is returned to its normal position by switch operating device B, the operation of the buffing device D is just the reverse of that described above, and will be readily understood from an inspection of the drawings.

If a vehicle trails through the switch when the switch occupies its normal position, the switch points are moved toward the right as viewed in Fig. 1, by the wheels of the vehiole. Under these conditions spring rod 12 of connecting rod 0 is held stationary by switch operating device B, so that spring 78 of spring connecting rod C becomes compressed and exerts a force on the switch points tending to return the switch points to their initial positions. WVhen the switch points move toward the right, the pistons 24 and 25 of bufling device D are moved toward the right a like amount. is held stationary, valve G of bufiing device D remains open during this movement. The fluid in cylinder 23 on the righthand side of piston 25 therefore flows through valve G into reservoir 23? until piston 25 has moved past the end of leak groove 23 whereupon fluid then also flows past piston 25 through this leak groove. The fluid in cylinder 23 on the right-hand side of piston24, during this movement, flows through leak groove 23 past piston 24 into cylinder 23 on the left-hand side of piston 24 until piston 24 has moved to the end of this groove, whereupon, the pressure of the fluid in reservoir 2 3 opens valve F and permits fluid to flow through ports and 34 into cylinder 23 on the left-hand side of piston 24. The pressure exerted on valve member 36 of valve F by spring 38 is comparatively small, sothat very little pressure is required to open valve F. It will be apparent, therefore, that the butfingdevice D offers very little resistance to the movement of the switch points away from their initial position under these con- Since spring rod 12 ditions'. As soon as the switch points start to return to their initial position due to the bias of spring 78, however, spring 38 closes valve F,so that fluid can not pass this valve and the return movement of-the switch points 0 is then. limited to the rate at which the fluid in cylinder 23 on the left-hand side of piston 24 can flow through regulating valve 58, until piston 24 has moved past the end of leak groove 23. .This rate may be varied by varying the number of'oriflces 58 which are qured for adjacent trucks of a vehicle to pass the switch points when the vehicle is moving at its usual speed.

hen the switch occupies its reverse posltion, valve F is open and valve G: is closed. If a vehicle trails through the switch under the conditions, the switch points are moved to the left. but the pistons 2i and are free to move toward the left and the buiiing device D therefore oilers practically no opposition to the movement of the switch points. But valve G is closed, and when the switch points start to return toward their initial positions, the fluid in cylinder 23 on the right-hand side of the piston 25 is forced through the regulating valve 63, thereby retarding this movement to the rate at which fiuid can flow through this valve. This rate may be varied by adjusting valve 63 as will be readily understood. I

It will be apparent, therefore, that with apparatus embodying my invention substantially no opposition is ofiered by the bufing device to normal manual operation of the switch, or to movement of the switch points away from either extreme position by a trailing railway vehicle, but the return movement of the points after a trailing move is retarded to a degree which can be accurately controlled by valves 63 and 58.

It should be pointed out that, while I have illustrated my invention as applied to a rail-- way switch, my invention is not limited to this use, but may be applied to any reciprocable device where similar buffing action is desired.

Although I have herein shown and described only one form of bufling device embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination with a railway switch movable between two extreme positions and connected with a switch operating device by resilient means, a buiiing device comprising a cylinder containing a fluid and fixed in the trackway, a reciprocable piston in said cylinder operatively connected with said switch, a reservoir, means including a restricted orifice for constantly connecting said cylinder with said reservoir, a cam operatively connected with said switch operating device, and a poppet valve controlled by said cam for at times providing an additional passage between said reservoir and said cylinder to vary the opposition offered by said fluid to movements of said piston in one direction.

2. combination with a railway switch movable between two extreme positions and connected with a switch operating device by resilient means, a buihng device comprising a cylinder containing a fluid and fixed in the trackway, a reciprocable piston in sa1d cylinder operatively connected with said swltch, a reservoir, means including a restricted orifice for constantly connecting said cylinder with said reservoir, a cam movable between two extreme positions and operatively connected with said switch operating device in such manner that said cam occupies one extreme position when said switch is moved to one extreme position by said switch operating device but that said cam occupies the other extreme position when said switch is moved to the other extreme position by said switch operating device, and a poppet valve for providing an additional passage between said reservoir and said cylinder to vary the opposition offered by said fluid to movements of said piston in one direction, said valve being controlled by said cam in such manner that said valve is opened when said cam occupies one extreme position but that said valve is closed when the cam occupies the other extreme position.

3. In combination with a railway switch movable between two extreme positions and operatively connected with a switch operating device through resilient means, a bufiing device comprising a cylinder containing a fluid, a first and second spaced pistons in said cylinder reciprocable between two extreme positions and connected with said switch, means at one end of said cylinder for permitting fluid to leak past said first piston for a portion of its stroke means at the other end of said cylinder for permitting fluid to leak past said second piston for a portion of its stroke, a reservoir, means for constantly con necting said cylinder between said pistons with said reservoir, means including a first restricted orifice for constantly connecting one end of said cylinder with said reservoir,

means including a second restricted orifice for constantly connecting the other end of said cylinder with said reservoir, a cam movable between two extreme positions and controlled by said switch operating device in such manner that said cam occupies one extreme position or the other according as said switch is moved to one extreme position or the other by said switch operating device, a first poppet valve operated by said cam in such manner that said first valve is opened when said cam occupies one extreme position but is closed when said cam occupies the other extreme position for at times providing an additional path between said one end of said cylinder and said reservoir to vary the resistance offered by said fluid to movements of said first piston in one direction, and a second poppet valve operated by said cam in such manner that said second valve is opened when said cam occupies said other xtreme position but is closed when said cam occupies saidone extreme position for at times providing an additional path between said other end of said cylinder and said reservoir to vary the resistance offered by said fluid to movements of said second piston in one direction.

4. The combination, with a railway switch comprising movable point and an operating device connected with said point through resilient means, of a bufling device supported in the trackway and comprising a cylinder containing fluid, a piston reciprocable in said cylinder and connected with said movable switch point, a reservoir, means including a restricted orifice for connecting said reservoir with one end of said cylinder, a valve controlled by said operating device, and a bypass around said restricted orifice and controlled by said valve. 7 V

5. In combination, a railway switch comprising a movable point, an operating device connected with said point through resilient means, apparatus for permitting free movement of said point in one direction while retarding movement of the point in the other direction, and means controlled by said operating device for rendering said apparatus ineffective to retard the movement of said point in such other direction 6. A railway switch comprising, a throw rod for connection with a pair of switch points, a spring mechanism operatively connected with the throw rod for yieldingly resisting movement of the latter in opposite directions by a train trailing through the switch and for returning the switch points to their original positions after the train has passed through the switch, and a dash pot mechanism for retarding the return movement of the throw rod in opposite directions.

7. A railway switch comprising, a throw rod for connection with a pair of switch points, a spring mechanism operatively connected with the throw rod for yieldingly resisting movement of the latter in opposite directions by a train trailingthrough the switch and for returning the switch points to their original positions after the train has passed through the switch, a dash pot mechanism for retarding the return movement of the throw rod in opposite directions, manually operated means for actuating the throw rod independently, of the spring mechanism, and means operatively connected with said man- 'ually operated means for automatically destroying the retarding force of the dash pot mechanism.

8. In a railway switch, the combination with a pair of switch points, of spring mechanism yieldingly resisting movement of the points in one direction and producing'movement thereof in the opposite direction, dash pot mechanism yieldingly resisting movement of the points in said opposite direction, manually operated means for changing the positions of the points to reverse the direcwith a pair of switch points, of. springrmechations inwhich movement'of the points is re.- sisted and produced by said spring means, and means operatively connecting the dash pot. mechanism with said manually operated means] whereby the, operation of the latter automatically reverses the direction. in which movement or the switch points is resistedby the dash-pot mechanism. 1 r

9. In a railway switch, the combination nism yieldinglyresisting movement of the points-in one. direction and producing; move;- ment thereof in the opposite direction, dash pot mechanism yieldingl'y resisting move;- ment, or the points in said opposite direction,

and manually operated means for changing the positions of the switch points and. re versing the directionm which movement of the, latter is resisted by the springmechanism and dash pot mechanism.

10. In a railway switch including a pair of switch points and further including a throw rod connecting the switch points, a spring mechanism selectively operable in opposite directions to close the switch after a train has trailed therethrough, a dash pot mechanism operatively connected with the throw rod for resisting the action of the spring mechanism to closethe switch, manually operated means operatively connected with the throw rod for throwing the switch, and means operatively connecting said manually operated means with the dash pot mechanism whereby the operation of said manually operated means automatically reverses the direction in which the action of the spring mechanism is resisted by the dash pot mechanism.

11. A railway switch comprising, a throw rod for connection with a pair of switch points, a spring mechanism operatively connected with the throw rod for yieldingly resisting movement of the latter in opposite directions by a train trailing through the switch and for returning the switch points to their original positions after the train has passed through the switch, a dash pot mechanism for retarding the return movement of the throw rod in opposite directions, said dash pot mechanism including a fluid chamher having a piston slidable therein and operatively connected with the throw rod, and means externally of the chamber to provide a passageway for the fluid from one end of the chamber to the other, said passageway being closed to one end of the chamber and being open to the other end thereof.

12. A railway switch comprising, a throw rod for connection with a pair of switch points, a spring mechanism operatively connected with the throw rod for yieldingly resisting movement of the latter in opposite directions by a train trailing through the switch, and for returning the switch points to their original positions after the train has i passed through the switch, a dash pot mechanism for retarding the return movement of the throw rod in opposite directions, said dash pot mechanism including a fluid chamher having a piston slidable therein and operatively connected withthe throw rod, means externally of the chamber to provide a passageway for the fluid from one end of the chamber to the other, said passageway being 110 closed to one end of the chamber and being open to the other end thereof, manually operated means for actuating the throw rod independently of the spring mechanism, and means operatively connected with said 15 manually operated means for opening the end of the fluid chamber closed to the passageway and for closing the end of the fluid chamber open to the passageway. In testimony whereof I aifix my signature.

WILLIAM C. MCWHIRTER.

i as 

